Document WO-A1-2011/007100 discloses connecting devices between metal tubes intended to protect an aircraft fuel piping from lightning. These devices include plastic connectors and metal connectors connecting the tubes to one another, having specified that the plastic connectors include a radially outer enclosure with two tips surrounding an inner tip, and are made from an injected composite material with a base of a thermoplastic matrix reinforced by discontinuous fibers with a length for example comprised between 3 and 5 mm. O-rings made from electrically insulating elastomer provide a tight connection between these connectors and the tubes that they connect to one another.